1. Field of the Invention
The present invention relates to a method for producing 1-.beta.-D-ribofuranosyl-1,2,4-triazoles of the formula ##STR3## wherein R represents a hydroxy, amino, or alkoxy group, by an enzymatic process.
2. Description of the Prior Art
1-.beta.-D-ribofuranosyl-1,2,4-triazoles of formula (I), especially 1-.beta.-D-ribofuranosyl-1,2,4-triazole-3-carboxamide, which is commonly known as Virazole, are valuable compounds used as broad-spectrum antiviral agents (Chem. & Eng. News, 50, 26, Apr. 17, 1972).
1-.beta.-D-Ribofuranosyl-1,2,4-triazoles may be produced by conventional synthetic methods, such as a method described in Witkowsky et al., 164th Am. Chem. Soc. Meeting, Boston, April, 1972. However, the known synthetic methods involve complex chemical processes and sometimes result in decreased yield as a result of by-product formation.
On the other hand, a fermentation process for the production of these triazole derivatives is known and is described in Japanese Published Examined Patent Application No. 17830/1979. This fermentation process comprises aerobically culturing bacteria of the genera Brevibacterium, Cornyebacterium, Arthrobacter, or Bacillus in a culture medium containing a 1,2,4-triazole of formula (II) ##STR4## wherein R is a hydroxy, amino, or alkoxy group, for 2 to 8 days and recovering accumulated 1-.beta.-D-ribofuranosyl-1,2,4-triazole from the culture broth. However, this fermentation process requires a long period of fermentation and complicated recovering steps to obtain purified product from the culture broth, which contains large amounts of various kinds of impurities.